1. Field of the Invention
The present invention relates to an algorithm used in a method of controlling a paper machine to automatically tune parameters for calculating the initial value of web moisture percentage at a dryer part inlet after grade change and parameters for calculating the dry-bulb temperature of air within a hood. The invention also relates to apparatus for implementing such an algorithm.
2. Description of the Prior Art
In the specification of Patent Application 2001-106038, the applicant proposed equation (1) shown below as an equation for calculating the initial value of a web's dryer part inlet moisture percentage after grade change.                               Initial          ⁢                                          ⁢          value          ⁢                                          ⁢          of          ⁢                                          ⁢                      web            ′                    ⁢          s          ⁢                                          ⁢          moisture          ⁢                                          ⁢          percentage                =                  MPNowInit          +                                    A              1                        ×                                                            BD                  2                                -                                  BD                  1                                                            BD                1                                              +                                    A              2                        ×                                                            V                  2                                -                                  V                  1                                                            V                1                                                                        (        1        )            where                BD1: Bone dry basis weight before grade change (g/m2)        BD2: Bone dry basis weight setpoint after grade change (g/m2)        V1: Machine speed before grade change (m/min)        V2: Machine speed setpoint after grade change (m/min)        MPNowInit: 50% (fixed)        A1, A2: Tuning parameters        
Also in the specification of Patent Application 2001-014493, the applicant proposed equation (2) shown below as an equation for calculating the dry-bulb temperature of air within a hood.                               Dry          ⁢                      -                    ⁢          bulb          ⁢                                          ⁢          temperature          ⁢                                          ⁢                                    T              a                        ⁡                          (              j              )                                      =                                            A              3                        ×                          (                                                                    T                    s                                    ⁡                                      (                    j                    )                                                  -                                                      T                    s                                    ⁢                                      Init                    ⁡                                          (                      j                      )                                                                                  )                                +                                    T              a                        ⁢                          Init              ⁡                              (                j                )                                      ⁢                                                  ⁢                          (                                                j                  =                  1                                ,                …                ⁢                                                                  ,                N                            )                                                          (        2        )            where                Ts(j): Steam pressure within drum        TsInit(j): Initial value of steam pressure within drum        TaInit(j): Initial value of dry-bulb temperature of air within hood        N: Number of mesh divisions        j: Mesh division number        A3: Parameter        